There are conventionally known vehicles that control a system, such as a braking system, using compressed air fed from a compressor. The compressed air may contain oil for lubricating the inside of the compressor. If the oil enters the system, malfunction may occur.
In order to prevent the oil from entering the system, it is preferable to separate and collect the oil using a product called APU (Air Processing Unit). However, the oil that the APU collects for maintenance of performance is discharged outside. The discharge of the oil is problematic in terms of environmental preservation. To cope with this, there is disclosed an oil catch apparatus that separates impurities temporarily collected by an oil catch part and exhausts only the air outside (see Patent Document 1).